The present application claims priority to an optical element covering member, as well as a backlight and a liquid crystal display each having the optical element covering member. In particular, the present application relates to an optical element covering member for improving the display characteristics of a liquid crystal display.
In liquid crystal displays, a number of optical elements have been used for improving viewing angle and luminance, and the like. As these optical elements, film-type and sheet-type ones such as diffusion films and prism sheets are used.
FIG. 20 shows a configuration of a known liquid crystal display. As shown in FIG. 20, the liquid crystal display an illuminating device 101 for emitting light, a diffusion plate 102 for diffusing the light emitted from the illuminating device 101, a plurality of optical elements 103 for converging and diffusing the light diffused by the diffusion plate 102, and a liquid crystal panel 104.
Meanwhile, there is a tendency that the weights and the sizes of optical elements increase as the size of image display devices become large in recent years. When the weight and size of the optical elements are increased, rigidity thereof is lowered, thereby causing the deformation of the optical elements. The deformation of the optical elements adversely affects the optical directivity on a display surface, resulting in a serious issue of the irregular luminance.
It has been proposed to improve the low rigidity of the optical elements by increasing the thicknesses of the optical elements. However, the proposal results in increase in the thicknesses of liquid crystal displays and impairs the advantages of the liquid crystal displays, namely, thinness and lightweight. From this reason, it has been proposed to improve the low rigidity of sheet-type or film-type optical elements by bonding optical elements by a transparent adhesive (refer to, for example, Japanese Unexamined Patent Application Publication No. 2005-301147).
However, in the technology disclosed in the publication, the optical elements are bonded together with the transparent adhesive. This will eventually thicken a liquid crystal display, not as thick as one in the method of increasing the thickness of the optical elements. Further, the display characteristics of the liquid crystal display may be deteriorated by the transparent adhesive.